Efficient Verifiable Dynamic Threshold Secret Sharing Scheme Based on Elliptic Curves

A dynamic threshold secret sharing (DTSS) scheme allows the secret to be updated without changing the shares. The first DTSS scheme was proposed by Laih et al. in ۱۹۹۱. Several other schemes based on different methods have been proposed since then. In ۲۰۰۷, Chen et al. proposed a verifiable DTSS scheme based on elliptic curves and bilinear maps, which is almost efficient. In this paper, we propose an alternative verifiable DTSS scheme using elliptic curves and bilinear maps. The proposed scheme is computationally secure, and the secret and/or threshold parameter can change to any arbitrary values multiple times. Furthermore, in our scheme, there is no secure channel and participants do not need to save any information or extra shares ahead of time. Since the running time is an important factor for practical applications, we provide a complexity comparison of our approach with respect to Chen et al.’s scheme. The comparison between the proposed scheme and that of Chen et al. indicates that the new scheme is more efficient, that it means, it has much lower computational complexity, as well as smaller storage requirements.

Keywords:

Dynamic threshold secret sharing , Elliptic curve , Bilinear pairing , Verifiable , Computational security